Floating pump plunger



Jan. 26', 1937. w. JONES ET AL 2,068,859

FLOAT ING PUMP PLUNGER Filed April 5, 1935 Patented Jan. 26, 1937 UNITED STATES PATENT OFFICE FLOATING PUMP PLUNGER Application April 5, 1935, Serial No. 14,770

3 Claims. (01.309-4) This invention relates to improvements in a floating plunger for a reciprocating pump.

The inside walls of pump barrels as previously constructed have been scored by the tubular plunger due to misalignment of the piston rod and pump barrel due to wearing of the moving parts and tipping or canting of the plunger to an angular position. It is an object of this invention to eliminate scoring of the inside of pump barrels caused by tipping or canting of the pump rod.

The invention will be fully understood from the following description taken in connection with the accompanying drawing in which latter: 16 Fig. 1 is a side elevational view partly in iongitudinal section of the self-centering plunger applied to the piston rod of a conventional pressure pump, the rod being shown fragmentarily in an elevation. Fig. 2 is a transverse sectional view taken along the line IIII of Fig. 1. Fig. 3 is a rod in its proper aligned position, and Fig. 4 is a side elevationalview showing the relative position of the self-centering plunger with respectto the head of the piston when the piston rod isat an angular position.

Referring particularly to the drawing reference numeral I designates a conventional pump piston rod which is threaded at one end to receive a lock vnut 2-. An angular flange or collar 4 is formed on the piston rod I inwardly from the threaded end of the rod.

A follower head is held rigidly against the collar 4 by the locked nut 2. The follower head comprises two follower sections 1 and t. The adjoining walls of the follower sections. 1 and 8 are grooved to form an annular recess l0. Each follower section 1 and 8 is provided with an annular shoulder portion Ii which projects into the an- 4o nular recess I 0 and an annular flange l2 protrudes radially outwardly fromthe shouldered portion ll of each follower section I and 8.

A tubular plunger l5 loosely fits within the recess II. The tubular plunger [6 is of greaterextemal diameter than the follower sections 1 and I and the inner wall l6'oi' the tubular plunger is of greater diameter than the diameter of the shoulders ll of the follower sections 1 and 8. The

tubular plunger I5 is shorter in length than the space between the annular flanges l2 of the follower sections 1 and 8. its a result of this construction suflicient clearance is provided between the annular plunger l5 and the adjoining portions of the follower-head to allow for a moving fit. Free movement 'of the tubular plunger ll side elevational view of the piston with the piston with respect to the follower head is permitted. The free tubular plunger It remains centered within the pump barrel 20 at all points of the stroke of the piston even though the piston becomes tipped or canted at an angular position. 5 Scoring of the inside of the pump barrel 20 is practically eliminated since the tubular plunger remains centered in the pump barrel 20 even though the piston rod becomes misaligned with the cylinder due to wearing. The tubular plunger 10 I5 acts as a cradle for the follower sections i' and 8 to rest upon at the shoulders ll upon misalignment of the piston rod I with respect to the cylinder 20. The tubular plunger I5 is thicker than the distance which the annular flange l2 extends 1:; beyond the shouldered portions ll so that the annular flanges I! do not wear against the walls of the cylinder 20 when the pump rod l is tipped or canted to an angular position.

By the construction described the free tubular 20 plunger l5 remains centered within the pump barrel 20 at all points of the stroke. The tubular plunger I5 does not form, an integral mass with the follower head. The plunger l 5 is self-centering and therefore scoring of the inside vof the 25 pump barrel is practically eliminated. The tubular plunger i5 is provided with a series of annular grooves It on its outside surface which act as liquid seals for low pressure pumps. The tubular plunger IS with the grooves I! only is 30 adaptable to .pumps operating at pressures to a maxim of approximately 125 pounds per square 1 For higher pressures and for high gravity liquids snap rings is are inserted into the grooves l8 to insure tightness. This design 35 of follower head eliminates the use of rubber and duck packingwhidh is worn down by friction necessitating frequent renewals as occurs particularly when the pump is in sour oil service. The plunger operates on a liquid sealing thereby pre- 40 venting wear of the parts. Replacement of the parts of the device merely requires removal of the nut 2 and the follower section 8.

Various changes in alternative arrangements may be made within the scope of the appended 45 claims in which it is our intention to claim all novelty inherent in the invention as broadly as the prior art permits.

We claim:

1. A pump plunger including a follower head, an annular recess in the side of the head, annular shoulders formed in the recess, adjacent the edges of the side walls thereof, adapted to freelyengage the inner edges of a rigid tubular plunger member of lesser length than the recess and 66 loosely disposed therein, said plunger member having a diameter substantially greater than that at the follower head and a thickness greater than the depth of the recess at the shoulders. 2. A pump plunger according to claim 1 in which the plunger member is provided with a plurality of spaced annular grooves in its side walls adapted to receive snap flt rings.

3. In a pump cylinder, a plunger comprising a follower head mounted on a pump rod, annular flanges at each end of the head, annular shoulders disposed inwardly 01 said flanges and adjaaccuse cent their outer edges, and a rigid tubular plunger member, loosely disposed between the flanges in variable engagement with said annular shoulders, having a diameter greater than said flanges and a thickness greater than the width of the flanges at the shoulders, whereby contact between the head and the cylinder walls is prevented during angular movement of the head with relation thereto.

WILLIAM JONES. JAMES SHARP. WILLIAM H. BOEHM. 

